1. Field of the Invention
This invention is related to payload delivery, primarily to or from a ship or other marine vessel. This invention is also related to the deployment of a smaller vessel or payload combination and to its recovery. This invention is also related to the inspection of payloads, vessels, flotsam or any other article before bringing the payload or other article into proximity with a larger vessel or platform to prevent damage to the primary platform, such as a mother ship from which a smaller vessel may operate.
2. Description of the Prior Art
There is presently no safe, cost-efficient craft and system, which allows military and commercial ships or helicopters to deploy, service, maintain, retrieve and exchange data and payloads with smaller vessels. The trend in marine and aquatic military operations is one where large vessels will have an increasing need to deploy smaller vessels, particularly unmanned ones, for a variety of purposes. Further, safety requirements for naval assets in a climate of terrorist attacks, including chemical, biological and explosive threats, are such that systems are needed whereby a large vessel can safely handle, inspect and exchange data and materials with other vessels and payloads under a variety of conditions. Safety requirements for military and commercial applications are such that increasing the stand-off distance between large and small vessels is of major importance. It is often the case that large vessels are required to come into close contact with vessels of unknown origin and with cargo of unknown provenance. Using the USS Cole as an example, small vessels that may contain explosives and are closely-coupled with a larger vessel at the waterline can exact an extreme amount of damage, particularly below the waterline, because of hydraulic properties. As the distance between a smaller vessel and a larger one increases, explosive forces and the damage they cause decrease geometrically and rapidly to insignificance. It is desirable to have a craft which will increase the stand-off distance of larger vessels from smaller ones, which may contain unknown hazards and personnel.
The advent of new types of remotely-operated systems dictate entirely new types of craft which will operate under extreme conditions, including but not limited to speed, sea state, wide payload variety, weather, darkness, and enemy fire. New types of remotely-operated vessels operate at, above and below the water's surface. They come in a variety of types and sizes, from ounces to tons. The trend is to smaller vessels. Further, types of hazards used as weapons can range from ounces, such as biological and radiological hazards, to tons, such as fertilizer explosives. Again, the trend for intentionally-deployed hazards is improving technology with decreased size with increased effectiveness.
The use of separate craft for each new vessel employed by military or commercial means is highly undesirable. Large ships are expensive, and their design and manufacture is a lengthy process. The large ship duty cycle can run for decades, however smaller vessels change much more rapidly, and a new design can be in service within months or years. Small vessel obsolescence and replacement takes place over a much shorter period than for larger vessels. It is highly desirable to have an inexpensive small craft which is a physical and data interface between large and small vessels.
For many, if not most, operations employing such smaller vessels, it will be necessary to deploy or recover the smaller vessel from a primary vessel or platform. U.S. Pat. No. 6,178,914 discloses a method of launching a small vessel, such as a rescue or working boat, from a larger ship while the ship is under way. A floating cradle is towed from the larger ship, and the boat or smaller vessel is launched or recovered while positioned in the floating cradle. Rudders are provided for steering the floating cradle via a yoke. However, there appears to be no suggestion that the floating cradle could be used in other than a towed capacity or for military and security operations, or as a smart platform for sensors, or for operating independently, i.e. untethered as a standalone craft. The cradle is “dumb”, and has no sensors, computers, or data links. The system employed in that patent also requires two cranes and would not provide for center of gravity adjustment under different load conditions. There no provision for handling a variety of auxiliary vessels or payloads, including personnel. There is no contemplation of operations either from platforms other than ships, or when absent a mother vessel. The floating cradle is positively buoyant and not capable of submerged operation, lacking trim tanks and diving planes. This towed sled is uni-directional along the mother ship's course, with marginal freedom to move laterally. It is only capable of launching and recovery from the rear. The coupling mechanism in U.S. Pat. No. 6,178,914 is particular to a specific vessel and does not contemplate multi-purpose use or remote operation.
Physically contacting or deploying and recovering a small vessel or objects fixed to the shore or bottom is problematic due to the physical characteristics of the water and vessels, particularly when the vessels are of disproportionate size. Water, a fluid medium, has current, tides and wave motion at the air/sea interface which regularly manifests itself as periodic, generally periodic, or irregular and chaotic. The motion significantly decreases as a vessel submerges. The mass and displacement characteristics of a larger vessel compared to a smaller one exacerbate differences in motion. While two vessels may be in the same body of water, the ambient conditions will often be different even at proximal locations. While a large vessel of 1,000 tons might roll gently at a certain sea state, a smaller vessel might rise and fall, pitch and roll at several hundred percent of its length, height or beam. Further, the relative motion between large and smaller vessels is localized, affected by the vessels themselves and can be significantly affected by any recovery device or mechanical connection between a smaller or larger vessel. It is highly desirable to have a “smart” payload handling craft, with propulsion and control surfaces, which can inspect cargo and compensate for the differences in the relative motions between larger vessels and payloads. The handling craft should be capable of operating at, above, and below the water's surface. Such a vessel should have a large operational envelope for efficiency and safety purposes.
Military establishments use traditional, non-modular systems, like “A-frames” or davit/block and tackle systems because there is no alternative. Some very expensive systems like the US Navy's Remote Mine Hunting System, have dedicated handling systems which are completely and intentionally exclusive to a particular device. Many expensive, but small military vessels, such as smart torpedo-like devices, are simply handled by men in rubber boats. Rapidly changing technology dictates that there is a need for a new craft to handle a variety of payloads including craft, but handling systems and craft must remain backwards-compatible to legacy systems.